2024-02-14 18:13:07

by Shivaprasad G Bhat

Subject: [PATCH v2] powerpc/iommu: Fix the iommu group reference leak during platform domain attach

The function spapr_tce_platform_iommu_attach_dev() is missing to call
iommu_group_put() when the domain is already set. This refcount leak
shows up with BUG_ON() during DLPAR remove operation as,

KernelBug: Kernel bug in state 'None': kernel BUG at arch/powerpc/platforms/pseries/iommu.c:100!
Oops: Exception in kernel mode, sig: 5 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=8192 NUMA pSeries
<snip>
Hardware name: IBM,9080-HEX POWER10 (raw) 0x800200 0xf000006 of:IBM,FW1060.00 (NH1060_016) hv:phyp pSeries
NIP: c0000000000ff4d4 LR: c0000000000ff4cc CTR: 0000000000000000
REGS: c0000013aed5f840 TRAP: 0700 Tainted: G I (6.8.0-rc3-autotest-g99bd3cb0d12e)
MSR: 8000000000029033 <SF,EE,ME,IR,DR,RI,LE> CR: 44002402 XER: 20040000
CFAR: c000000000a0d170 IRQMASK: 0
GPR00: c0000000000ff4cc c0000013aed5fae0 c000000001512700 c0000013aa362138
GPR04: 0000000000000000 0000000000000000 0000000000000000 0000000119c8afd0
GPR08: 0000000000000000 c000001284442b00 0000000000000001 0000000000001003
GPR12: 0000000300000000 c0000018ffff2f00 0000000000000000 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR24: c0000013aed5fc40 0000000000000002 0000000000000000 c000000002757d90
GPR28: c0000000000ff440 c000000002757cb8 c00000183799c1a0 c0000013aa362b00
NIP [c0000000000ff4d4] iommu_reconfig_notifier+0x94/0x200
LR [c0000000000ff4cc] iommu_reconfig_notifier+0x8c/0x200
Call Trace:
[c0000013aed5fae0] [c0000000000ff4cc] iommu_reconfig_notifier+0x8c/0x200 (unreliable)
[c0000013aed5fb10] [c0000000001a27b0] notifier_call_chain+0xb8/0x19c
[c0000013aed5fb70] [c0000000001a2a78] blocking_notifier_call_chain+0x64/0x98
[c0000013aed5fbb0] [c000000000c4a898] of_reconfig_notify+0x44/0xdc
[c0000013aed5fc20] [c000000000c4add4] of_detach_node+0x78/0xb0
[c0000013aed5fc70] [c0000000000f96a8] ofdt_write.part.0+0x86c/0xbb8
[c0000013aed5fce0] [c00000000069b4bc] proc_reg_write+0xf4/0x150
[c0000013aed5fd10] [c0000000005bfeb4] vfs_write+0xf8/0x488
[c0000013aed5fdc0] [c0000000005c0570] ksys_write+0x84/0x140
[c0000013aed5fe10] [c000000000033358] system_call_exception+0x138/0x330
[c0000013aed5fe50] [c00000000000d05c] system_call_vectored_common+0x15c/0x2ec
--- interrupt: 3000 at 0x20000433acb4
<snip>
---[ end trace 0000000000000000 ]---

The patch makes the iommu_group_get() call only when using it there by
avoiding the leak.

Fixes: a8ca9fc9134c ("powerpc/iommu: Do not do platform domain attach atctions after probe")
Reported-by: Venkat Rao Bagalkote <[email protected]>
Closes: https://lore.kernel.org/all/[email protected]
Signed-off-by: Shivaprasad G Bhat <[email protected]>
---
Changelog:
v1: https://lore.kernel.org/all/[email protected]/
- Minor refactor to call the iommu_group_get() only if required.
- Updated the title, description and signature(Closes/Reported-by).

arch/powerpc/kernel/iommu.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index d71eac3b2887..37fae3bd89c6 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1285,13 +1285,14 @@ spapr_tce_platform_iommu_attach_dev(struct iommu_domain *platform_domain,
struct device *dev)
{
struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
- struct iommu_group *grp = iommu_group_get(dev);
struct iommu_table_group *table_group;
+ struct iommu_group *grp;

/* At first attach the ownership is already set */
if (!domain)
return 0;

+ grp = iommu_group_get(dev);
table_group = iommu_group_get_iommudata(grp);
/*
* The domain being set to PLATFORM from earlier

2024-02-14 18:13:56

by Jason Gunthorpe

Subject: Re: [PATCH v2] powerpc/iommu: Fix the iommu group reference leak during platform domain attach

On Wed, Feb 14, 2024 at 12:09:24PM -0600, Shivaprasad G Bhat wrote:
> The function spapr_tce_platform_iommu_attach_dev() is missing to call
> iommu_group_put() when the domain is already set. This refcount leak
> shows up with BUG_ON() during DLPAR remove operation as,
>
> KernelBug: Kernel bug in state 'None': kernel BUG at arch/powerpc/platforms/pseries/iommu.c:100!
> Oops: Exception in kernel mode, sig: 5 [#1]
> LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=8192 NUMA pSeries
> <snip>
> Hardware name: IBM,9080-HEX POWER10 (raw) 0x800200 0xf000006 of:IBM,FW1060.00 (NH1060_016) hv:phyp pSeries
> NIP: c0000000000ff4d4 LR: c0000000000ff4cc CTR: 0000000000000000
> REGS: c0000013aed5f840 TRAP: 0700 Tainted: G I (6.8.0-rc3-autotest-g99bd3cb0d12e)
> MSR: 8000000000029033 <SF,EE,ME,IR,DR,RI,LE> CR: 44002402 XER: 20040000
> CFAR: c000000000a0d170 IRQMASK: 0
> GPR00: c0000000000ff4cc c0000013aed5fae0 c000000001512700 c0000013aa362138
> GPR04: 0000000000000000 0000000000000000 0000000000000000 0000000119c8afd0
> GPR08: 0000000000000000 c000001284442b00 0000000000000001 0000000000001003
> GPR12: 0000000300000000 c0000018ffff2f00 0000000000000000 0000000000000000
> GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> GPR24: c0000013aed5fc40 0000000000000002 0000000000000000 c000000002757d90
> GPR28: c0000000000ff440 c000000002757cb8 c00000183799c1a0 c0000013aa362b00
> NIP [c0000000000ff4d4] iommu_reconfig_notifier+0x94/0x200
> LR [c0000000000ff4cc] iommu_reconfig_notifier+0x8c/0x200
> Call Trace:
> [c0000013aed5fae0] [c0000000000ff4cc] iommu_reconfig_notifier+0x8c/0x200 (unreliable)
> [c0000013aed5fb10] [c0000000001a27b0] notifier_call_chain+0xb8/0x19c
> [c0000013aed5fb70] [c0000000001a2a78] blocking_notifier_call_chain+0x64/0x98
> [c0000013aed5fbb0] [c000000000c4a898] of_reconfig_notify+0x44/0xdc
> [c0000013aed5fc20] [c000000000c4add4] of_detach_node+0x78/0xb0
> [c0000013aed5fc70] [c0000000000f96a8] ofdt_write.part.0+0x86c/0xbb8
> [c0000013aed5fce0] [c00000000069b4bc] proc_reg_write+0xf4/0x150
> [c0000013aed5fd10] [c0000000005bfeb4] vfs_write+0xf8/0x488
> [c0000013aed5fdc0] [c0000000005c0570] ksys_write+0x84/0x140
> [c0000013aed5fe10] [c000000000033358] system_call_exception+0x138/0x330
> [c0000013aed5fe50] [c00000000000d05c] system_call_vectored_common+0x15c/0x2ec
> --- interrupt: 3000 at 0x20000433acb4
> <snip>
> ---[ end trace 0000000000000000 ]---
>
> The patch makes the iommu_group_get() call only when using it there by
> avoiding the leak.
>
> Fixes: a8ca9fc9134c ("powerpc/iommu: Do not do platform domain attach atctions after probe")
> Reported-by: Venkat Rao Bagalkote <[email protected]>
> Closes: https://lore.kernel.org/all/[email protected]
> Signed-off-by: Shivaprasad G Bhat <[email protected]>
> ---
> Changelog:
> v1: https://lore.kernel.org/all/[email protected]/
> - Minor refactor to call the iommu_group_get() only if required.
> - Updated the title, description and signature(Closes/Reported-by).
>
> arch/powerpc/kernel/iommu.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)

Reviewed-by: Jason Gunthorpe <[email protected]>

Thanks again,
Jason

2024-02-15 02:34:01

by Michael Ellerman

Subject: Re: [PATCH v2] powerpc/iommu: Fix the iommu group reference leak during platform domain attach

Shivaprasad G Bhat <[email protected]> writes:
> The function spapr_tce_platform_iommu_attach_dev() is missing to call
> iommu_group_put() when the domain is already set. This refcount leak
> shows up with BUG_ON() during DLPAR remove operation as,
>
> KernelBug: Kernel bug in state 'None': kernel BUG at arch/powerpc/platforms/pseries/iommu.c:100!
> Oops: Exception in kernel mode, sig: 5 [#1]
> LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=8192 NUMA pSeries
> <snip>
> Hardware name: IBM,9080-HEX POWER10 (raw) 0x800200 0xf000006 of:IBM,FW1060.00 (NH1060_016) hv:phyp pSeries
> NIP: c0000000000ff4d4 LR: c0000000000ff4cc CTR: 0000000000000000
> REGS: c0000013aed5f840 TRAP: 0700 Tainted: G I (6.8.0-rc3-autotest-g99bd3cb0d12e)
> MSR: 8000000000029033 <SF,EE,ME,IR,DR,RI,LE> CR: 44002402 XER: 20040000
> CFAR: c000000000a0d170 IRQMASK: 0
> GPR00: c0000000000ff4cc c0000013aed5fae0 c000000001512700 c0000013aa362138
> GPR04: 0000000000000000 0000000000000000 0000000000000000 0000000119c8afd0
> GPR08: 0000000000000000 c000001284442b00 0000000000000001 0000000000001003
> GPR12: 0000000300000000 c0000018ffff2f00 0000000000000000 0000000000000000
> GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> GPR24: c0000013aed5fc40 0000000000000002 0000000000000000 c000000002757d90
> GPR28: c0000000000ff440 c000000002757cb8 c00000183799c1a0 c0000013aa362b00
> NIP [c0000000000ff4d4] iommu_reconfig_notifier+0x94/0x200
> LR [c0000000000ff4cc] iommu_reconfig_notifier+0x8c/0x200
> Call Trace:
> [c0000013aed5fae0] [c0000000000ff4cc] iommu_reconfig_notifier+0x8c/0x200 (unreliable)
> [c0000013aed5fb10] [c0000000001a27b0] notifier_call_chain+0xb8/0x19c
> [c0000013aed5fb70] [c0000000001a2a78] blocking_notifier_call_chain+0x64/0x98
> [c0000013aed5fbb0] [c000000000c4a898] of_reconfig_notify+0x44/0xdc
> [c0000013aed5fc20] [c000000000c4add4] of_detach_node+0x78/0xb0
> [c0000013aed5fc70] [c0000000000f96a8] ofdt_write.part.0+0x86c/0xbb8
> [c0000013aed5fce0] [c00000000069b4bc] proc_reg_write+0xf4/0x150
> [c0000013aed5fd10] [c0000000005bfeb4] vfs_write+0xf8/0x488
> [c0000013aed5fdc0] [c0000000005c0570] ksys_write+0x84/0x140
> [c0000013aed5fe10] [c000000000033358] system_call_exception+0x138/0x330
> [c0000013aed5fe50] [c00000000000d05c] system_call_vectored_common+0x15c/0x2ec
> --- interrupt: 3000 at 0x20000433acb4
> <snip>
> ---[ end trace 0000000000000000 ]---
>
> The patch makes the iommu_group_get() call only when using it there by
> avoiding the leak.
>
> Fixes: a8ca9fc9134c ("powerpc/iommu: Do not do platform domain attach atctions after probe")
> Reported-by: Venkat Rao Bagalkote <[email protected]>
> Closes: https://lore.kernel.org/all/[email protected]
> Signed-off-by: Shivaprasad G Bhat <[email protected]>
> ---
> Changelog:
> v1: https://lore.kernel.org/all/[email protected]/
> - Minor refactor to call the iommu_group_get() only if required.
> - Updated the title, description and signature(Closes/Reported-by).

Sorry I already applied v1.

If you send this as a patch on top of v1 with a new change log I can
merge it as a cleanup/rework.

cheers

2024-02-15 13:58:13

by Shivaprasad G Bhat

Subject: Re: [PATCH v2] powerpc/iommu: Fix the iommu group reference leak during platform domain attach

On 2/15/24 08:01, Michael Ellerman wrote:
> Shivaprasad G Bhat <[email protected]> writes:
>> The function spapr_tce_platform_iommu_attach_dev() is missing to call
>> iommu_group_put() when the domain is already set. This refcount leak
>> shows up with BUG_ON() during DLPAR remove operation as,
<snip>
>> [c0000013aed5fd10] [c0000000005bfeb4] vfs_write+0xf8/0x488
>> [c0000013aed5fdc0] [c0000000005c0570] ksys_write+0x84/0x140
>> [c0000013aed5fe10] [c000000000033358] system_call_exception+0x138/0x330
>> [c0000013aed5fe50] [c00000000000d05c] system_call_vectored_common+0x15c/0x2ec
>> --- interrupt: 3000 at 0x20000433acb4
>> <snip>
>> ---[ end trace 0000000000000000 ]---
>>
>> The patch makes the iommu_group_get() call only when using it there by
>> avoiding the leak.
>>
>> Fixes: a8ca9fc9134c ("powerpc/iommu: Do not do platform domain attach atctions after probe")
>> Reported-by: Venkat Rao Bagalkote <[email protected]>
>> Closes: https://lore.kernel.org/all/[email protected]
>> Signed-off-by: Shivaprasad G Bhat <[email protected]>
>> ---
>> Changelog:
>> v1: https://lore.kernel.org/all/[email protected]/
>> - Minor refactor to call the iommu_group_get() only if required.
>> - Updated the title, description and signature(Closes/Reported-by).
> Sorry I already applied v1.
>
> If you send this as a patch on top of v1 with a new change log I can
> merge it as a cleanup/rework.

I have posted the cleanup patch at
https://lore.kernel.org/linux-iommu/[email protected]/

Thank you!

Shivaprasad

> cheers